[tunaoftheland]

I am ignorant of SLIME/CIDER (though I think I've used the latter with Clojure). Do they have access to the same memory space as the running application and the ability to interact with live application state? It seem that Nightlight has that as a goal. My (limited) understanding is that SLIME/CIDER run in a separate process from the application, thus requiring IPC back and forth between Emacs and the application runtime.

[qwertyuiop924]

That's true, but the practical effect (having access to application internals, interacting with live program state, the ability to connect to a live program and hotpatch it, even if it's running on a remote server (but you'll really want the source files if you're doing that, and you should be sure to upload the new sources/binary to the server you just hotpatched, or you'll be in for a shock when it reboots), and so on) is exactly the same, and they mostly share the same capabilities (AFAICT, Nightlight might have better autocomplete than SLIME/Geiser, but other than that, I can't think of anything).